Factor completely. $16x^6-81=$
Explanation: $16x^6-81 = ({4x^3})^2-({9})^2$ Using the difference of squares pattern: $({4x^3})^2 - ({9})^2 =({4x^3}+{9})({4x^3}-{9})$ In conclusion, $16x^6-81=(4x^3+9)(4x^3-9)$ Remember that you can always check your factorization by expanding it.